[c-nsp] cisco regex puzzle of the day

[Saku Ytti]

On (2015-03-12 01:12 +0000), Mack McBride wrote:

Hey,

> The junos expression in question DOES NOT involve backtracking.
> After a match there is no need to backtrack.
> 
> The expression in question goes character by character excluding the 64500.
> Note the last part matches 6 digit ASNs that start with 64500.

I think we miscommunicated. Originally I explained IOS does not work, because
it does backtracking, not talking about JunOS at all.
Then you mentioned that particular JunOS example does not do backtracking,
which I understood you claiming JunOS does not support backtracking at all

So to summarize, both IOS and JunOS do backtracking, and it cannot be turned
off. But indeed, ^64500+ [^64500] does not require backtracking, 64500+ never
needs to be unconsumed to satisfy the [^64500]

-- 
  ++ytti